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BaTiO3 crystals are important photorefractive materials due to their self-pumped phase-conjugation and large electro-optic coefficient. High gain, fast response time and proper beam fanning BaTiO3 crystals are desirable. We fabricated photorefractive BaTiO3:Ru single crystals and then investigated their optical and photorefractive properties. In as-grown Ru-doped BaTiO3 single crystals, the absorption shoulder is around 450 nm. The dark conductivity is dominant in the crystal and much higher than the photo conductivity at a low intensity pumping beam. [Copyright &y& Elsevier]

Abstract: In this study we are able, using a copper grid substrate, to successfully grow separate nanowires with a high level of crystallinity, for a length of up to 10μm. They were synthesized under various temperatures. We compare and contrast three types of geometries (micron-, nano-scale, and tip-like single CuO nanowires), to identify their potential for monitoring the size effects of quantum confinements. The confocal Raman spectrometry results confirm the expected outcome, that reducing of the diameter of a cylindrical cross-section of a single nanowire results in Raman frequency downshifts. The results can be explained by the bond polarizability model. The applicability of investigating the size effects of the quantum confinement of the tip-like geometry of a single nanowire without any preparation for different sizes of nanoparticles is possible because the detection is relatively straightforward and the reproduced Raman signals can be observed. [Copyright &y& Elsevier]

Abstract: We have demonstrated the enhancement of light output of InGaN-based blue light-emitting diodes (LEDs) using different trimethylgallium (TMGa) flow rates in the growth of p-AlGaN epilayer to facilitate a rougher p-GaN surface. It is found that higher output power can be achieved from the LEDs with rougher surface morphologies when the TMGa flow rate (R TMGa) is increased up to 60sccm during p-Al0.05Ga0.95N epilayer growth. Such a rough surface obtained at higher R TMGa is attributed to the fact that the vertical growth rate is faster than the lateral growth rate, thus, leading to the facet of crystal growth focuses mainly in the vertical direction. The output power of devices biased at 20mA is 15.4, 15.9, 17.5, and 18.9mW for TMGa flow rates of 10, 20, 40, and 60sccm, respectively. [Copyright &y& Elsevier]